I sincerely hope somebody helps you out. But in the meantime, there is an alternative. Assuming you are playing a version of GTA-IV on a PC, you can go to the loading option and re-load the game from the last auto-save, which should be automatically placed in the last possible save slot in the game save directory. This will often store the 'final state' of any previous mission, and even if you are out in the middle of nowhere, place you back in your nearest or most current safe house when re-loaded into the machine. Now, the last save will also put you in a position to attempt the failed mission because it is, logically, next on your list of things to do in game.
I hope this helps and wish you the best of luck with the resolution of his issue.